A study published in British Food Journal and reported by foodnavigator.com casts doubt on whether giving consumers more nutritional information will lead to healthier eating habits, and I generally agree.
To me, the issues underlying obesity and other evidence of poor nutritional habits are only mildly exacerbated by consumers' not knowing what's in what they're eating.
Apple? Good. Apple Pie? Less good. Yes, there are lots more detail one could add, but that level of information would be enough for most people, if they considered it important.
Now, there are really good questions to ask — i.e. "is refined sugar safe to consume at the levels Americans are consuming it?" — but nutrition labeling is not where they will be answered.